Sinapis alba  (Brassica hirta) white mustard Brassicaceae SIAL*; Bx, pb;

Sinapis alba.en.wikipedia.org

Sinapis alba.en.wikipedia.org. (Accessed 4/2014).

Sinapis alba is an annual herb to 70 cm tall, rough-hairy. 

Leaves alternate, lower leaves to 20 cm long, deeply pinnately divided, leaflets toothed, stalked, widest above middle, leaves smaller upwards and less divided, becoming stalkless. 

Flowers yellow, 1.5 cm wide, 4-parted; blooming June-Aug. 

Fruit dry, capsules 2-parted, to 1.5 cm long, bristly-hairy, each side 3-veined, constricted between seeds, beak to 2 cm long, flat, often curved, tip pointed, seeds, 4-8, 0.2 cm long. 

Wetland status: UPL. 

Frequency in NYC: Very infrequent. 

Origin: Europe. 

Habitat: Open soil, roadsides. Sometimes cultivated for mustard seed or salad greens.